Conventionally, when an impeller of such a fluid power transmission is produced, as disclosed in Patent Document 1 below, a plurality of blades are first aligned in a standing state on a fixed position of an inside face of a shell, a core is subsequently laid over the group of these blades so as to fit a projecting piece of each blade into a latching hole of the core, and following this brazing is carried out between the projecting piece and the latching hole and between the blade and the shell respectively.